[Intel-gfx] [PATCH igt v2] lib: Force global reset + uevents for hang detector

[Chris Wilson]

The hang detector relies on a uevent for notification and aborting the
test. As proposed, fine-grained resets may not produce a global uevent
and so this hang detection becomes void. As we don't expect any hang, we
can just reduce the reset to only a global + uevent and so maintain
functionality, and switch back to fine-grained resets afterwards.

Note that any test that requires testing fine-grained resets should
ensure that they are enabled first as igt may leave the global
parameters in an inconsistent state.

v2: Restore fine-grained resets for explict igt_allow_hang()

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Michel Thierry <michel.thierry at intel.com>
---
 lib/igt_aux.c   | 10 ++++++++
 lib/igt_gt.c    |  4 ++++
 lib/igt_sysfs.c | 72 ++++++++++++++++++++++++++++++++++++++++++---------------
 lib/igt_sysfs.h |  6 +++++
 4 files changed, 74 insertions(+), 18 deletions(-)

diff --git a/lib/igt_aux.c b/lib/igt_aux.c
index 1222806c..b1b63db5 100644
--- a/lib/igt_aux.c
+++ b/lib/igt_aux.c
@@ -60,6 +60,7 @@
 #include "igt_debugfs.h"
 #include "igt_gt.h"
 #include "igt_rand.h"
+#include "igt_sysfs.h"
 #include "config.h"
 #include "intel_reg.h"
 #include "ioctl_wrappers.h"
@@ -449,6 +450,15 @@ void igt_fork_hang_detector(int fd)
 
 	igt_assert(fstat(fd, &st) == 0);
 
+	/*
+	 * Disable per-engine reset to force an error uevent. We don't
+	 * expect to get any hangs whilst the detector is enabled (if we do
+	 * they are a test failure!) and so the loss of per-engine reset
+	 * functionality is not an issue.
+	 */
+	igt_assert(igt_sysfs_set_parameter
+		   (fd, "reset", "%d", 1 /* only global reset */));
+
 	signal(SIGIO, sig_abort);
 	igt_fork_helper(&hang_detector)
 		hang_detector_process(getppid(), st.st_rdev);
diff --git a/lib/igt_gt.c b/lib/igt_gt.c
index 11643edd..65743d07 100644
--- a/lib/igt_gt.c
+++ b/lib/igt_gt.c
@@ -21,6 +21,7 @@
  * IN THE SOFTWARE.
  */
 
+#include <limits.h>
 #include <string.h>
 #include <signal.h>
 #include <errno.h>
@@ -161,6 +162,9 @@ igt_hang_t igt_allow_hang(int fd, unsigned ctx, unsigned flags)
 	struct local_i915_gem_context_param param;
 	unsigned ban;
 
+	igt_assert(igt_sysfs_set_parameter
+		   (fd, "reset", "%d", INT_MAX /* any reset method */));
+
 	if (!igt_check_boolean_env_var("IGT_HANG", true))
 		igt_skip("hang injection disabled by user");
 	gem_context_require_bannable(fd);
diff --git a/lib/igt_sysfs.c b/lib/igt_sysfs.c
index 8ebc5b4f..15ed34be 100644
--- a/lib/igt_sysfs.c
+++ b/lib/igt_sysfs.c
@@ -139,6 +139,35 @@ int igt_sysfs_open(int device, int *idx)
 }
 
 /**
+ * igt_sysfs_set_parameters:
+ * @device: fd of the device (or -1 to default to Intel)
+ * @parameter: the name of the parameter to set
+ * @fmt: printf-esque format string
+ *
+ * Returns true on success
+ */
+bool igt_sysfs_set_parameter(int device,
+			     const char *parameter,
+			     const char *fmt, ...)
+{
+	va_list ap;
+	int dir;
+	int ret;
+
+	dir = igt_sysfs_open_parameters(device);
+	if (dir < 0)
+		return false;
+
+	va_start(ap, fmt);
+	ret = igt_sysfs_vprintf(dir, parameter, fmt, ap);
+	va_end(ap);
+
+	close(dir);
+
+	return ret > 0;
+}
+
+/**
  * igt_sysfs_open_parameters:
  * @device: fd of the device (or -1 to default to Intel)
  *
@@ -336,19 +365,7 @@ int igt_sysfs_scanf(int dir, const char *attr, const char *fmt, ...)
 	return ret;
 }
 
-/**
- * igt_sysfs_printf:
- * @dir: directory for the device from igt_sysfs_open()
- * @attr: name of the sysfs node to open
- * @fmt: printf format string
- * @...: Additional paramaters to store the scaned input values
- *
- * printf() wrapper for sysfs.
- * 
- * Returns:
- * Number of characters written, negative value on error.
- */
-int igt_sysfs_printf(int dir, const char *attr, const char *fmt, ...)
+int igt_sysfs_vprintf(int dir, const char *attr, const char *fmt, va_list ap)
 {
 	FILE *file;
 	int fd;
@@ -360,12 +377,7 @@ int igt_sysfs_printf(int dir, const char *attr, const char *fmt, ...)
 
 	file = fdopen(fd, "w");
 	if (file) {
-		va_list ap;
-
-		va_start(ap, fmt);
 		ret = vfprintf(file, fmt, ap);
-		va_end(ap);
-
 		fclose(file);
 	}
 	close(fd);
@@ -374,6 +386,30 @@ int igt_sysfs_printf(int dir, const char *attr, const char *fmt, ...)
 }
 
 /**
+ * igt_sysfs_printf:
+ * @dir: directory for the device from igt_sysfs_open()
+ * @attr: name of the sysfs node to open
+ * @fmt: printf format string
+ * @...: Additional paramaters to store the scaned input values
+ *
+ * printf() wrapper for sysfs.
+ *
+ * Returns:
+ * Number of characters written, negative value on error.
+ */
+int igt_sysfs_printf(int dir, const char *attr, const char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, fmt);
+	ret = igt_sysfs_vprintf(dir, attr, fmt, ap);
+	va_end(ap);
+
+	return ret;
+}
+
+/**
  * igt_sysfs_get_u32:
  * @dir: directory for the device from igt_sysfs_open()
  * @attr: name of the sysfs node to open
diff --git a/lib/igt_sysfs.h b/lib/igt_sysfs.h
index 4089535d..d666438a 100644
--- a/lib/igt_sysfs.h
+++ b/lib/igt_sysfs.h
@@ -29,6 +29,10 @@
 
 int igt_sysfs_open(int device, int *idx);
 int igt_sysfs_open_parameters(int device);
+bool igt_sysfs_set_parameter(int device,
+			     const char *parameter,
+			     const char *fmt, ...)
+	__attribute__((format(printf,3,4)));
 
 int igt_sysfs_read(int dir, const char *attr, void *data, int len);
 int igt_sysfs_write(int dir, const char *attr, const void *data, int len);
@@ -38,6 +42,8 @@ char *igt_sysfs_get(int dir, const char *attr);
 
 int igt_sysfs_scanf(int dir, const char *attr, const char *fmt, ...)
 	__attribute__((format(scanf,3,4)));
+int igt_sysfs_vprintf(int dir, const char *attr, const char *fmt, va_list ap)
+	__attribute__((format(printf,3,0)));
 int igt_sysfs_printf(int dir, const char *attr, const char *fmt, ...)
 	__attribute__((format(printf,3,4)));
 
-- 
2.11.0